Lithium and a Lover
by Monochromatic Pylon
Summary: Mukuro visited Tsuna after a mission. 6927


**Title:** Lithium and a Lover  
**Fandom:** Katekyo Hitman Reborn  
**Characters/Pairings:** 6927  
**Rating:** R  
**Warnings:** yaoi, sexual situation, no sense whatsoever, silly mistakes...  
**Disclaimers:** I do not own KHR. "Lithium and a Lover" is taken from Sirenia's song title.

Previously posted at my livejournal acc as a birthday fic for MyraHellsing last month. :3 Give her love.

Posted here as per request (nagging, more like lol) from my friend. Huhu.

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The cat was suddenly in his face licking the tip of his nose. In an odd effusive way, it marched across the oak desk, knocked over papers and pens, swished its tail over his hand. Then, it settled down at the center of the table, looking directly into his eyes.

Tsuna sighed, and turned to the window. It was opened. White curtain billowed in gentle breeze. The sun had almost set fully, rendering the sky in gradients of orange to dark blue. He did not realize it before, but now that he had, it felt slightly dark inside his office.

His eyes felt watery from all the constant work, and his back was sore. Rubbing his eyes with a hand while holding back a groan, Tsuna shifted back his glance to the red and blue eyes of the cat. Black furs rimmed feline eyes, meshing perfectly into soot like little nose and twisted mouth. One canine protruded from said mouth in a mockery of a smirk. Never before in his life had Tsuna seen a cat maintained that kind of arrogant expression. But then, this cat was… not exactly a cat.

"Mukuro, I'll appreciate it if you use the door like other people normally would," said Tsuna firmly despite his exhaustion. It had been a long day of paper works and even longer days of sleepless nights for him.

The cat gave him a meow that sounded suspiciously like a chuckle. Glassy eyes blinked once to him, then the cat, or by now should be called Mukuro, leaped from his desk to land smoothly on a leather chair provided for a guest at the other side.

Faint mist filled the air around the cat, covering the cat from his vision until what's left was no more than a figure. The figure grew bigger and bigger until it no longer resembled a cat, but that of a man –and when the mist cleared, Mukuro emerged.

"Good evening, little Vongola," he greeted, leisurely propping his chin by a hand while his elbows resting against the armrests.

Tsuna was hardly 'little' anymore after all the years he spent as the Tenth successor of Vongola throne. He had grown considerably taller, stronger, and perhaps wiser. Although he knew he would never surpass his guardians in height, still, calling him 'little' at the age of twenty something was a little bit infuriating.

"Good to see you back. How was your mission going?" Tsuna asked. Hand lowered back to his desk.

"I never allow a failure," the long haired man answered easily. His trademark sly upturning of lips was plastered upon his face.

"I will never expect less from you."

"Kufufu," Mukuro laughed. "That is very well put."

"I take you will write a detailed report as soon as you can then..."

"Written report is such a hassle," Mukuro said in distaste.

"Mmm, you still have to do it though. Reborn will have my head and yours if you don't," Tsuna said.

"The arcobaleno still pesters you, hmm?"

Pestering was an understatement, really.

"He said as long as I stayed a No Good Tsuna, he would continue training me," Tsuna answered, pushing his seat backward to rise.

Mukuro's eyes followed him as he ambled to a small round wooden table at the side of the room. On top of the table were a flask and a set of cups. Tsuna took the flask and opened it, pouring amber liquid into a cup.

"Do you want?" he offered.

"No, thank you."

"I like tea," Tsuna declared absently. "Especially the kind which Kusakabe-san always kindly gets for me."

"Kufufu, I prefer unrefined ol' Russian Vodka actually," Mukuro informed.

Tsuna chuckled softly and sipped from his cup, before settling it down on the table again.

"Mukuro, do you need something?" he asked. The other man never normally sought him out after mission, well, never for a report, not for an idle chat. "You aren't here just for an idle chat, are you? And I believe you never promptly drop by to report after a mission."

"You hurt my feeling," Mukuro protested, but his saccharine smile betrayed his words.

Tsuna lifted his eyebrows. "Are you really?"

"Kufufufu," Mukuro laughed. "I have phobias and perhaps hysteria, but I am not afraid of loneliness, Vongola. Contrary to what you think."

Tsuna tilted his head slightly, wondering why those words suddenly came out from the other's mouth. However, it was true Tsuna sometimes assumed Mukuro was a man who was afraid of loneliness despite how the older man wouldn't admit it himself. (How Mukuro attained this knowledge, Tsuna didn't want to know). Chrome, Ken, and Chikusa. Mukuro didn't have any reason to save them and keep them around. But he did, and that alone should have raised a question.

"But I do sometimes feel lonely though," Mukuro continued.

Tsuna blinked. "What can I do for you?"

"Give me a lot of lithium," the man answered easily, "Or perhaps a lover."

Incredulity filled Tsuna's mind as he tried to process Mukuro's words.

Mukuro chuckled at the lack of reaction. "What can you provide me?"

Tsuna was silent while he gave the man a measuring stare. Sparks of mischief were alighted on Mukuro's face. The brunet sighed weakly.

He walked the short distance toward Mukuro with resignation, eyes never leaving the other man, who in turn followed his every movement with his own. Tsuna registered slight surprise on Mukuro's expression when he tentatively lowered himself to the other man's lap. The leather chair made little sound underneath the added weight. He sat with his side facing the man, legs bumping against the armrest.

Tsuna blushed a little despite himself, at the sudden boldness that sang through him. He lifted a hand to caress Mukuro's face, while the other lodged itself behind the Mist Guardian's neck, feeling the silky strands that had grown longer, longer during the years.

Tsuna brought his face closer to the other man's for a prelude of a kiss. Mukuro responded by slight upturning of face and an arm circling Tsuna's waist; his smirk never faltered.

The Tenth Boss of Vongola deliberated his action for three seconds, lips hovering above the others while he mentally trying to decide. _The dice had been thrown, there was no turning back._

"You're the worst," Tsuna mumbled quietly under his breath, and closed their distance.

The setting had changed quickly from his office to his bedroom, on his bed, in a flurry of movement. Tsuna did not exactly understand what had triggered him to do what he did, perhaps something in Mukuro's words or perhaps something else. This was not the first time he did this with the man, even though this was definitely the first time he responded upon the implications (or rather frequently, innuendos) thrown at him by the resident Mist Guardian.

"Are you scared?" Enquired the Mist teasingly.

Blinking once, Tsuna shook his head. "I wasn't before. And I don't think I'm going to be."

Mukuro ran his hand down Tsuna side, inflicting a shudder within the younger man. Tsuna's shirt had been lost somewhere in their passion and now the contact brought by Mukuro's ungloved hand was unbearable to hold.

Tsuna flinched as Mukuro swoop down to dab a wet tongue into his belly button and dragged it up, leaving a trail of glistening saliva upon the skin of stomach and chest. The fall of Mukuro's coat swept his skin, and he let out a low moan involuntarily, lifting his both his hands to grab Mukuro's shoulder.

"You should have been afraid of me," the Mist spoke against his neck.

"W-what?" Tsuna stuttered out, hitching a breath when Mukuro unleashed his teeth into the play, nibbling the jugular skin.

Mukuro chuckled, moving his face from Tsuna's neck so he could meet his boss' eyes. "I want to possess you, remember? Hmm?"

Tsuna narrowed his eyes. "You won't," he said.

Mukuro smiled in response, as unreadable as ever.

"Right?" The brunet added in search of confirmation. Often, he couldn't understand the Mist Guardian. The man was exasperatingly capricious, all games and hidden meanings as if he was afraid to state something and thus made it definable.

The Mist Guardian chose that moment to dig his fingers into Tsuna's hips, earning a yelp from Tsuna. And before Tsuna could say anything more, he leaned down to kiss the younger man.

Mukuro moved his lips against Tsuna's aggressively, hungrily.

Tsuna clenched Mukuro's shoulder harder, the stiff material of Mukuro's coat bunching up under his fingers, and returned the kiss. He felt Mukuro take his bottom lip between his teeth, then slowly run the tip of his tongue between the flesh. A small gasp escaped his mouth –but it was quickly swallowed as Mukuro parted his lips again, darting his tongue into Tsuna's mouth. Tsuna's hand moved up, fingers twining in dark hair as the kiss deepened.

By the time they parted, Tsuna was out of breath. He opened his eyes and met Mukuro's uneven stare once again.

"What kind of answer was that?" he whispered breathlessly.

Mukuro lifted one side of his lips in an amused expression. "I won't, for now. I have other more pleasurable thing to take," Mukuro said.

Tsuna blinked once, warmth blooming from his neck up into his cheek—_how can he say that so casually?_—and broke their eye contact. He turned his face to the side.

The Illusionist let out a laugh. "Am I upsetting you?"

Tsuna turned to face Mukuro again. "You talk a lot tonight."

"Am I? Kufufufu, you always bring out the worst of me," Mukuro said carelessly as he nuzzled his nose against Tsuna's collarbone.

"Is that a good thing?" Tsuna asked. His right hand crept up to join the other one at Mukuro's hair, hugging the Illusionist's head.

"Probably."

Mukuro unlatched himself from his grip. Spidery fingers crawled from Tsuna's hip down to the hem of his pants. Mukuro deftly worked Tsuna's belt open and pulled it away; Tsuna lifted his hips slightly to assist Mukuro. The other man thanked him by kissing his stomach. He drew his belly in as he felt Mukuro sucked the skin there, leaving prominent mark against his pale complexion.

"Mukuro…" Tsuna mumbled.

"Impatient are we?" Mukuro said.

"N-No."

"It's okay, Vongola. I'm going to make you feel good. Just lie back and enjoy," Mukuro said teasingly. He surged up again to plant a light kiss on Tsuna's mouth. His thumb brushed Tsuna's nipple, rousing an odd sensation in its wake.

Tsuna clenched the sheets as Mukuro slipped one leg between his boss' and ground his knee against Tsuna's groin, causing a jolt of pleasure to run past Tsuna's spine. Mukuro repeated it, and this time Tsuna moaned. Mukuro chuckled.

"Guh. S-Stop that," Tsuna protested.

"Why would I? It earns a good reaction from you," Mukuro replied and applied another pressure to prove his words. Tsuna groaned.

"Y-you're so impossible sometimes."

"Kufufufu~"

Mukuro splayed his hands upon Tsuna's stomach, fingers tracing the red mark he had left, and down to undo Tsuna's pants. Without warning, he snaked a hand into his boss' pants, fingers closing around already hard member. He worked a firm and relentless rhythm from the start, rubbing and pumping faster, faster, faster.

Litany of moans escaped Tsuna's lips. He screwed shut his eyes in pleasure, arms growing limp at the sides. The hand around his cock burned him like wildfire, churning out fiery heat that reduced his coherence to mere ashes, and before long, Tsuna felt his body gave tiny spasms. He came over the edge with a loud grunt, spilling his semen messily over his stomach and Mukuro's clothed front.

"That was fast," Mukuro commented.

Gradually, Tsuna became aware of his hard breathing filling the air around them. He took a minute to calm himself before opening his eyes to the world again, and he was greeted with a sight of Mukuro darting his tongue along his wet fingers, lapping off Tsuna's residue.

Blushing a fraction at the display, Tsuna said, "It's not fair."

"How come?" Mukuro chuckled.

"Take off your clothes," the brunet commanded.

Afterwards, Tsuna lay in the loose embrace of Mukuro's arm draping over him, spent and sore. He sighed and planted his face on Mukuro's bare chest, still wet and slippery with perspiration from their previous extersion, letting the other's steady heartbeat lulled him.

"You've grown a lot of backbone," Mukuro suddenly spoke.

Tsuna had been half asleep. He opened his eyes again and made an inquisitive sound, "Hmm?"

"I miss my pliant and sweet little Vongola," Mukuro said with faked sadness in his tone. His hand slid into Tsuna's hair, dragged down his back, caressed the juncture of his spine, and moved down to rest at Tsuna's bottom.

"Mukuro," Tsuna spoke tiredly, trying to ignore the sensation Mukuro inflicted. "Shut up and sleep."

"Kufufu~ See what I meant?"

END?

Note: According to Wikipedia, lithium salts such as lithium carbonate, lithium citrate, and lithium orotate are used as antidepressant for bipolar treatment. Unlike most other mood altering drugs, they counter both mania and depression.


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